Reaction time in gait initiation depends on the time available for affective processing

• Published in: Neuroscience letters 2015-11, Vol.609, p.69-73
• Main Authors: Gélat, Thierry, Chapus, Carole Ferrel
• Format: Article
• Language: English
• Subjects: Adolescent; Affect; Bioengineering; Biomechanics; Emotion; Emotion regulation; Female; Gait; Gait initiation; Human health and pathology; Humans; Imaging; Life Sciences; Male; Mechanics; Physics; Postural control; Posture; Reaction Time; Tissues and Organs; Young Adult
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2015.10.003

•Reaction time depends on the delay between emotional image onset and start signal.•When this delay was 0.5s a congruency effect for reaction time appeared.•When this delay was 3s the congruency effect disappeared.•An emotion regulation strategy is thought to be implemented for unpleasant pictures.•This strategy revealed a change of image valence appraisal and initial posture. Previous studies have reported that reaction time in gait initiation was affected by emotion eliciting pictures. This study examined the effect of a change in the delay between image onset and the imperative “go” on reaction time. From a standing posture, 19 young adults had to walk (several steps) toward pleasant or unpleasant images in two conditions. In the short condition, the word “go” appeared 500ms after image onset and participants were instructed to initiate gait as soon as possible after the word go appeared. In the long condition, the same procedure was used but the word “go” appeared 3000ms after image onset. Results demonstrated that motor responses were faster for pleasant pictures than unpleasant ones in the short condition. In contrast, no significant difference was found between both categories of pictures in the long condition. Moreover, we found that self ratings of valence of unpleasant pictures were less unpleasant in the long condition than in the short one whereas there was no difference for pleasant pictures between both conditions. This result reflected a change in the affective significance of unpleasant pictures in the long condition. We also found in the long condition, that the body was inclined forward and to the stance limb during the standing posture and importantly with a similar extent for pleasant and unpleasant pictures. This change clearly reflected a facilitation of the gait initiation process. Overall, results suggested that this gait facilitation when confronted to unpleasant pictures resulted from emotional regulation processes enabling to reappraise these pictures and to override the initial avoidance tendency that they caused.